cables MCQs – Page 2

Practise focused cables questions with marked answers for exam preparation and subject revision.

cables Mcqs
21. In congested areas where excavation is expensive and inconvenient draw in system of laying of underground cables is often adopted
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A. Yes

B. No

22. In the cables, sheaths are used to___________?
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A. provide enough strength

B. none of the above

C. prevent the moisture from entering the cable

D. provide proper insulation

23. PVC stands for____________?
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A. positive voltage conductor

B. pressed and varnished cloth

C. post varnish conductor

D. polyvinyl chloride

E. none of the above

24. The advantage of oil filled cables is_________?
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A. more perfect impregnation

B. smaller overall size

C. all of the above

D. no ionisation, oxidation and formation of voids

25. Conduit pipes are normally used to protect _______ cables
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A. PVC sheathed cables

B. all of the above

C. unsheathed cables

D. armoured

26. In capacitance grading a homogeneous dielectric is used
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A. Yes

B. No
27. The material for armouring on cable is usually__________?
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A. any of the above

B. none of the above

C. galvanised steel wire

D. steel tape

28. Which of the following protects a cable against mechanical injury___________?
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A. Armouring

B. Bedding

C. None of the above

D. Sheath

29. The surge resistance of cable is__________?
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A. 100 ohms

B. 50 ohms

C. 5 ohms

D. 20 ohms

30. A cable carrying alternating current has__________?
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A. hysteresis, leakage, copper and friction losses

B. hysteresis losses only

C. hysteresis and leakage losses only

D. hysteresis, leakage and copper losses only

31. Pressure cables are generally not used beyond__________?
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A. 66 kV

B. 33 kV

C. 132 kV

D. 11 kV

32. The breakdown of insulation of the cable can be avoided economically by the use of___________?
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A. inter-sheaths

B. insulating materials with different dielectric constants

C. both (A) and (B)

D. none of the above

33. The minimum dielectric stress in a cable is at_____________?
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A. conductor surface

B. bedding

C. lead sheath

D. armour

34. Solid type cables are considered unreliable beyond 66 kV because___________?
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A. skin effect dominates on the conductor

B. there is a danger of breakdown of insulation due to the presence of voids

C. of corona loss between conductor and sheath material

D. insulation may melt due to higher temperature

35. The thickness of metallic shielding on cables is usually_______________?
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A. 0.04 mm

B. 3 to 5 mm

C. 40 to 60 mm

D. 0.2 to 0.4 mm

36. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ____________?
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A. Compressed SFe gas

B. Polyvinyle chloride

C. Impregnated paper

D. none of the above

E. Vulcanised rubber

37. The current carrying capacity of cables in D.C. is more than that in A.C. mainly due to__________?
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A. absence of harmonics

B. none of the above

C. non-existence of any stability limit

D. absence of ripples

E. smaller dielectric loss
38. Natural rubber is obtained from milky sap of tropical trees
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A. Yes

B. No

39. The metallic sheath may be made of lead or lead alloy or of aluminium ?
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A. Yes

B. No
40. Cables for 220 kV lines are invariably____________?
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A. none of the above

B. rubber insulated

C. compressed oil or compressed gas insulated

D. mica insulated

E. paper insulated